Folding scaffold



A ril 4, 1967 L. s. WAUN FOLDING SCAFFOLD 5 Sheets-Sheet 1 Filed Aug. 2, 1965 April 4, 1967 L. s w UN 3,312,305

FOLDI NG S CAFFOLD Filed Aug. 2, 1965 5 Sheets-Sheet 2 lm/enfor. L50 5 04am y 1477955. Crag? A ril 4, 1967 L. s. WAUNY 3,

FOLDING SGAFFOLD Filed Aug. 2, 1965 3 Sheets-Sheet s United States Patent 3,312,305 FOLDING SCAFFOLD Leo S. Waun, 14939 University, Allen Park, Mich. 48101 Filed Aug. 2, 1965, Ser. No. 476,266 11 Claims. (Cl. 182-15) The present invention relates to a novelly constructed folding scaffold which is extremely safe to use and handle and also to a method of collapsing the same.

Prior proposed folding scaffolds used for painting and cleaning the inside of buildings and along the outside walls thereof possess certain objectionable features. Among the problems encountered are: relatively poor safety features making use and handling hazardous, especially by elderly persons; awkward and time consuming to fold and unfold, often requiring partial or complete disassembly; cumbersome to move from place to place, particularly when passing through narrow doorways; inconvenient and uncomfortable to use and to ascend and descend; economically prohibitive to a large numberof potential consumers; and relatively poor versatility, e.g.

inability to readily accommodate different floor elevations (for example, stairways) and different working elevations above the floor.

With the foregoing in mind, it is a primary object of this invention to provide a novel folding scaffold and a unique method of collapsing the same which substantially overcome most of the problems mentioned above and which alleviate the remaining problems.

It is a further significant object of this invention to provide a mobile folding scaffold having excellent safety features.

An additional important object of this invention is the provision of a folding scaffold which is easily folded and unfolded, by one person, without alterations or disassembly.

It is also an object of this invention to provide a novel folding scaffold having one or more of the following features: services a large working area; sturdy; restrained against inadvertent collapsing or opening when respectively in the unfolded and folded positions; highly compact when folded; adjustable to accommodate different floor elevations and different heights above the floor; readily movable from place to place and room to room in the unfolded position; restrained against inadvertent shifting during use by weight-actuated brakes; and convenient and comfortable to use.

These .and other objects and features of the present invention will become more fully apparent from the following description and appended claims taken in conjunction with the accompanying drawings wherein:

FIGURE 1 is a perspective representation of the presently preferred folding scaffold embodiment of the present invention in its fully open position;

FIGURE 2 is an enlarged bottom view of the central hinge of the scaffold work platform taken along line 2-2 of FIGURE 1;

FIGURE 3 is an enlarged fragmentary perspective of the pivot joint between each guard rail and each rear vertical support at the access opening;

FIGURE 4 is an enlarged fragmentary the central hinge of each guard rail;

FIGURE 5 is an enlarged fragmentary perspective, partially broken away for clarity, of one extensible diagonal strut comprising part of the scaffold frame;

FIGURE 6 is an enlarged fragmentary elevation particularly illustrating one of the extensible telescopic legs of the scaffold of FIGURE 1;

FIGURE 7 is an enlarged fragmentary perspective particularly illustrating one of the scaffold wheels and weightactuated brakes of the scaffold of FIGURE 1;

perspective of FIGURE 8 is an elevation of the scaffold of FIGURE 1 in a partially collapsed position;

FIGURE 9 is an elevation of the scaffold of FIGURE 1 in its fully collapsed position;

FIGURE 10 is an enlarged fragmentary elevation of a second presently preferred telescopic leg construction; and

FIGURE 11 is an enlarged fragmentary side elevation, partly in section, taken along lines 11-11 of FIGURE 10.

THE EMBODIMENT OF FIGURES 1-9 With the foregoing objects in mind, reference is now made to the drawings wherein like parts are designated with corresponding numerals throughout. FIGURE 1 illustrates in perspective a presently preferred scaffold, generally designated 10, in its restrained unfolded or work position.

The scaffold 10 comprises a substantially rigid frame, generally designated 12, the scaffold being positionable in three distinct positions (ie, the work position of FIG- URE 1, the partially folded position of FIGURE 8 and the completely folded restrained position of FIGURE 9). The frame 12 comprises substantially vertical or upright support members '14, two being disposed at each end of the scaffold.

The upright support members 14 at the forward end or front of the scaffold are integrally connected at the top and at the bottom by an ar-cuate shaped member 16 and a transverse channel support 18, respectively. The transverse support 18 is preferably welded to the front supports 14.

The upright support members 14 at the rearward end of the scaffold are independent of each other at the top thereby providing an access opening 20 through which the user ascends and descends the scaffold. A safety belt 22 is preferably provided at the access opening 20, the safety belt 22 being provided with snap hooks 24 at each end for releasable attachment to the two eye hooks 26. The shank of each eye hook 26 is rigidly secured by suitable means, such as by threaded or bolt connection, to the rear upright support 14, as depicted in FIGURE 1.

The rear upright support members 14 are joined one to another by transverse channel member 30, the channel member being integrally secured, preferably by welding, to the two rear upright support members 14.

A pair of cross members 32, one at each end of the scaffold and a constituting part of a platform support generally designated 34, are .pivotally connected by suitable means to the respective upright support members 14 disposed at the two ends of the scaffold. As can be seen in'FIGURES 1 and 2, the platform support 34 comprises a plurality of beam members 36 which are generally coextensive though slightly angularly disposed one with respect to the other, all spanning the space between the front cross member 32 and the central platform support hinge, generally designated 38.

Similarly a plurality of beam members 40, which are substantially coextensive though slightly angularly disposed one with another span the distance between the rear cross member 32 and the central platform support hinge 38.

The beam members 36 and 40 integrally carry a sectionalized work platform, generally designated 42, the beam members 36 being rigidly secured by suitable means to the forward section 44 of the platform and the beam members 40 correspondingly being rigidly attached by suitable means such as countersunk bolts or the like, to the rear platform section 46. Both platform sections 44 and 46 may be formed of any suitable material such as plywood, sheet aluminum or sheet steel, lightweight materials being preferred. Suitable plastic materials, preferably of the thermosetting type, may also be utilized.

The platform sections 44 and 46 are separated from each other by a joint space 48, when the scaffold is in the unfolded position of FIGURES l and 2. The platform section 46 is provided with an aperture 50 of suitable size for purposes to be explained subsequently and also with a metal wear plate 51 where wood or like material with poor abrasion resistance is used at the platform surface.

With particular reference to FIGURE 2, the central platform support hinge 38 comprises an elongated transverse pin 52 which passes through transversely aligned apertures in each of the beam members 36 and 40. Spacers 54 and 56 concentrically surround the pin 52 and retain the beam members 36 and 40 in their related transverse position regardless of whether the scaffold 10 is in the unfolded or the folded position or anywhere in between. A block 58 is pivotally carried at each end of the pin 52 for purposes which will be described subsequently, being retained by cotter pins 59, each of which passes through an aperture at one end of the pin 52.

The ends of the two outside beam members 40 adjacent the joint space 48 are integrally secured, by bolts or like means to an end plate 60, which is L-shaped in cross section; This plate 60 accommodates unitary movement of the beam members 40 during folding and unfolding of the scaffold. Recesses 62 in the plate 60 receive the beam members 36 when the scaffold 10-is in the fully unfolded position.

Thus, the work platform 42 readily accommodates folding and unfolding action by a single person without dismembering or disassemblying any of the components of the platform or of the scaffold frame 12.

A pair of sectionalized, centrally hinged guard rails, generally designated 70, are pivotally connected at front and rear connections 72 and 74 to respective ones of the front and back upright support members 14 at the top thereof. Each guard rail 70 is also provided with a central hinge generally designated 76 in FIGURE 1. Each guard rail 70 also comprises a front guard rail section 73 and a rear guard rail section 75, each being illustrated in the drawings as having a tubular configuration. The centrally hinged guard rails 70 enclose the two sides of the scaffold 10, preferably at a height above the work platform 42 which corresponds approximately to the waist height of a human being of average size.

The connection 72 may be any suitable pivotable connection but is preferably a pin connection, the pin rotatably passing through the support 14 and the guard rail and being threadingly secured in position by nuts or the like disposed at each end. A suitable spacer, concentric of the pin, is preferably interposed between the guard rail 70 and the arcuate member 16.

The preferred rear guard rail hinge 74 is depicted in enlarged fragmentary perspective in FIGURE 3. By inspection of FIGURE 3, it is readily apparent that the vertical support member 14 is bifurcated at its upper end so as to terminate in spaced lugs 80. A single lug 82 integrally projects from the rear guard rail section 75 between the spaced lugs 80. A pin 84 extends through aligned apertures in the three lugs 80, and 82 and is retained in such position by suitable means, such as by press fitting the pin into position, enlarging the ends of the pins, or by utilization of snap rings. Thus, the connection 74 of each guard rail 70 is readily pivoted to accommodate folding and unfolding of the scaffold 10.

The central hinge connect-ion 76 is depicted in enlarged fragmentary perspective in FIGURE 4 to which reference is now made. Integral lugs 86 and 88 respectively project from the guard rail sections 73 and 75, being secured thereto preferably by welding. A pivot bolt 90 extends through aligned apertures in the lugs with suitable spacers concentrically surrounding the bolt 90 to facilitate easy pivotal movement. A shield 92 integrally extends from the guard rail section 75 a distance sufficient to cover the top portion of the connection 76.

, 59. Each vertical strut 94 is integrally united to its associated block 59, preferably by welding, the block being rotatably carried upon the transverse pin 52. By reason of the connection, wrought by the struts 94, between each central hinge 76 of the guard rails 70 and the central hinge 38 of the platform, the guard rail sections 73 and and the platform sections 44 and 46 fold and unfold jointly as the scaffold 10 is displaced between its extended and its collapsed positions. Thus, unitary movement is insured and binding between the hinged parts is substantially alleviated during folding andunfolding.

Returning to FIGURE 1, the presently preferred embodiment of this invention includes a material holding platform, generally designated 100. The platform comprises a planar support 102 fabricated of any suitable material such as wood or sheet metal. Front brackets 104 and rear brackets 106 are integrally joined to the planar member 102 by suitable means, such as rivets or bolts. The front brackets 106 are pin connected at 108 to the front upright support members 14 while the rear brackets 104 are respectively pivotably united at aperture 110 to a hanger 112.

Each hanger 112 comprises a flexible metal rod with a reverse bend '114 adapted to fit over and hang from a pin 116, which pin is integrally carried by the guard rail section 73. Naturally, the hangers 112 may be manually rotated, associated and disassociated with the pin 116 to accommodate pivotal displacement about the pins 108 of the material holding platform 100 between the horizontal position depicted in solid lines in FIGURE 1 and the vertical position depicted in dotted lines. While the platform 100 is illustrated as extending, in its horizontal position, between the front and rear upright support members 14, it is to be appreciated that a suitable material holding platform could be provided which would extend beyond the front or at one side of the scaffold 10, if desired.

As evident from FIGURE 1, a diagonal brace 120, of fixed length, is pivotally connected at 122 by suitable means to the outside of each front upright support member 14 'at an intermediate location along the length thereof. Each brace is also pivotally connected at 124 by suitable means to the outside of the adjacent guard rail section 75 intermediate the length thereof. The two diagonal braces 120 at each side of the scaffold thus accommodate freedom from binding as the scaffold 10 is folded and unfolded.

A pair of extensible-retractable diagonal struts, generally designated 130, are respectively pivotably connected to the inside of one rear upright support member 14, at

t 132, by suitable means and to the inside of the guard rail section 73, at 134, also by suitable means. Each diagonal strut terminates in an angularly disposed end 136 adjacent the pivot joint 134.

For the detailed description of the diagonal strut 130, reference is made to FIGURE 5. The diagonal strut 130 comprises a composite rod having a central hollow tubular member 140 of relatively large diameter, an upper tubular member 142 and a lower tubular member 144. The lower end of the tube 142 and the upper end of the tube 144 are so sized as to slideably fit within the respective ends of the central tube140 (see FIGURE 5). The central tube 140 has top and bottom slots 146 at the upper end thereof (only the top slot being perceptible in FIG- URE 5). A pin or bolt 148 passes through the slots 146 in spaced relation to the side edges of each slot. The pin 148 also extends through transversely aligned apertures 150 in the lower end of the upper tube 142. Thus, the

slots 146 in conjunction with the pin 148, which is secured in place by suitable retaining means, combined to accommodate relative radial rotation of the central tube 140 with respect to the upper tube 142 for purposes later to be explained.

A pivot 152 joins a flexible plate 154 to the lower tube 144 near the upper end thereof. The flexible plate 154 integrally carries a detent pin 156 which, when the scaffold is in the unfolded position of FIGURE 1, extends through apertures 158 and 160 respectively of the tubes 140 and 144. Thus, in this position, the detent pin 156 prevents both relative axial and relative rotational movement be tween the tubes 140 and 144 and, also prevents relative rotational movement between the tubes 140 and 142. Hence, the detent pin 156 of the two diagonal struts 130 retains the entire scaffold in its fully unfolded, work position where situated as depicted in FIGURE 5.

When the detent pin 156 is manually depressed downward a sufficient distance, the central tubular member 140 may be rotated relative to both tubes 142 and 144, a distance defined by the arcuate length of the slots 146. Such rotation displaces the aperture 160 out of radial alignment with the aperture 158 thereby retaining the detent pin 156 in its depressed relation. In this way, relative sliding movement between the tubes 140 and 144 is accommodated. Thus, progressive folding of the scaffold 10 incrementally extends the effective length of each diagonal strut 130 and progressive unfolding of the scaffold incrementally reduces the effective length of each diagonal strut 130.

When the scaffold has been fully unfolded, for example from the position of FIGURE 9 to that of FIGURE 1, the central tube 140 is merely manually rotated until the aperture 1 60 is brought into radial alignment with the aperture 158 allowing the flexible leaf spring 154 to urge the detent pin 156 through the apertures 158 and 160 into the position of FIGURE 5. In this position the entire scaffold is retained in rigid relation and thus inadvertent unfolding of the scaffold during use or transport is prohibited.

It is to be appreciated that while each front diagonal brace 120 is illustrated and described as being of fixed length, a structural member of variable length, such as member similar to 130, may be utilized.

The lower end 170 of each upright support member 14 terminates in a leg generally designated 172, which leg is preferably of the extensible-retractable type. Each leg 172 terminates in a castor 174, the castor being any suit able commercially available type supported by and pivotably connected to the leg 'by a bifurcated support and bearing member 175.

Specific reference is made to FIGURES 6 and 7, which fragmentarily illustrate one presently preferred telescopically extensible leg construction 172. The castor 174 is suitably supported by a tubular member 17 6, which, in the case of the rear wheels 174, is integrally connected to a rod 178 which rod pivotably joins the castor at the support 175. A coiled compression spring 180 concentrically surrounds the rod 178 for a purpose later to be described. An upper flange (not shown) of the rod 178 rotatably retains a threaded fitting 182 in concentric relation to the rod. The fitting 182 has threads (not shown) which engage interior threads (not shown) at the lower end of the tube 176.

The tube 176 has a series of spaced and aligned detent apertures 184, the tube being sized to slideably fit within the upright support member 14. The upright support member 14 also is provided an aperture 186 (FIGURE 7) aligned with an aperture 188 in the channel transverse support 30.

The transverse supports 18 and 30 each carry a pair of brackets 190, for example by bolt connection. Each bracket 190 at its distal end 192 slideably supports a detent pin 194 in an aperture 195. The pin 194 is biased by a spring 196 toward the left as viewed in FIGURE 7, the spring being urged against a washer 198, concentric circumscribing the pin 194, and the inside face of the bracket 190. In use, the pin 194 is positioned as depicted in FIGURE 7 with the one end thereof passing through aligned apertures 184, 186, and 188. The pin 194 may be manually retracted from the aperture 184 to accommodate elevating or lowering of the scaffold. When the desired detent aperture 184 has been positioned in alignment with the apertures 1 86 and 188 the pin 194 is released and is displaced into the aligned aperture 184 by action of the spring 196. Thus, the location of the adjoining castor 174 with respect to the Work platform 72 is easily readjusted. Cotter pins 197 pass through the pin 194 at the outside surface of the bracket end 192 and at the side of the side of the washer 198 opposite the spring 196 (not shown) to define the extent to which the pin 194 may be manually retracted and extended by action of the spring 196. The effective length of each telescopic leg 172 may be individually adjusted, in the manner explained above, to accommodate leveling of the platform when different floor elevations are encountered, as, for example, when the scaffold is positioned upon a stairway. Likewise, the telescopic legs also accommodate positioning of the scaffold platform at any one of a plurality of selected heights with respect to the floor. No auxiliary extension frames or the like are required.

When two oppositely disposed telescopic legs 172 are extended a significant distance, as schematically illustrated in FIGURE 6, a spring biased, extensible rung 200 or the like may be used to suitably join the two telescoping tubes 176 to rigidi-fy the scaffold.

Any and all of the castors 174 may be provided with a weight-actuated brake, generally designated 210, a presently preferred brake being particularly illustrated in FIGURE 7 as installed at the rear legs 172.

Each weight-actuated brake 210 comprises a generally Z-shaped bracket 212, the one end 214 being apertured to loosely receive a previously-described rod 178 above the castor 174. The other end 216 of the bracket 212 carries a resilient castor-engaging stop 220, which stop is rigidly secured to the bracket by suitable means such as a bolt. The threaded end of a flat-head bolt 222 extends through an aperture (not shown) in the castor frame is secured therein by nuts 224. The shank of the bolt 222 extends through a slot 226 in the bracket 212 and terminates in a flat head 228 having a diameter greater than the transverse dimension of the slot 226. The bolt 222 rigidifies the brake bracket 212. At the same time the slot 226 accommodates relative movement between the bracket 212 and the bolt 222. .When the user of the scaffold ascends the scaffold his weight compresses the spring between the castor frame 175 and the bracket 212 (the spring rate thereof being relatively low to accommodate such action). This causes the tube 176 to be displaced downwardly relative to the rod 178. The bracket 212 is correspondingly displaced downwardly. I11 this way, the resilient stop 220 is brought into pressurized surface-to-surface contact with the castor wheel. Thus, rotation of the wheel is prevented and the scaffold will remain stationary while it is being used.

OPERATION OF THE EMBODIMENT OF FIGURES l9 The operation required to unfold the previously described scaffold 10 may best be understood by contrasting FIGURES 1, 8 and 9. Since the manipulative steps required to fold the scaffold 10 are substantially identical with the manipulative steps required to unfold the scaffold, being attended to in reverse order, only the folding operation will be described.

Procedurally, the detent pin 156 at each diagonal strut 130 is manually depressed and the central tube140 of each extensible diagonal strut 130 is rotated with respect to both the upper and the lower tubes 142 and 144, the slots 146 and the pin 148 accommodating such 7 rotation. Thisun'locks the entire scaffold from its restrained fully unfolded position of FIGURE 1.

' The user, preferably standing adjacent the access opening 20 grips thefplatform section 46 at the aperture'50 and lifts. Upward force exerted by the user at the aperture .50 causes the respective ends of the scaffold to relatively rectilinearly move one toward the other, initially assuming the general position of FIG- URE 8. Relative displacement of the ends of the scaffold toward each other is accompanied by rotation of the platform section 44 and the beam members 36 in one direction about the central platform hinge 38 and by rotation-of the platform section 46 and the beam members 40 in the'opposite direction about the hinge 38, as the hinge 38 is elevated.

Simultaneously, the central hinge 76 of each guard rail 70. is-correspondingly elevated, through the aid of the vertical struts 94, the front guard rails sections 73 pivoting counterclockwise and the rear sections 75 clockwise about their central guard rail hinge 76.

Note that the scaffold initially assumes the somewhat angular position with respect to the vertical as folding begins (see FIGURE 8) by reason of the fact that the two diagonal braces 120 have fixed lengths while the diagonalstruts 130 are of variable lengths. Thus during the described folding action, the struts 130 each telescopically extend, the tube 144 being slidingly displaced downward within the tube 140.

Progressive collapsing of the scaffold 10 ultimately brings the front and rear ends of the scaffold into side-byside relation as depicted in FIGURE 9, the front upright vertical support members 14 and the front rail. sections 73 first assuming the position depicted in dotted lines in FIGURE 9. In this position the rail section '73 is disposed at a slight acute angle to the right with respect to a plane passing through the center line of each front member 14.

' As can be readily appreciated by inspection of FIG- URE, 9, by reason of the fixed length of each diagonal brace 120, folding of the scaffold 10 results in the castors 174 at the front being lifted a distance above the floor while the rear castors 174 remain in contact with the floor.

With the forward wheels 174 off the ground and the rear wheels 174 engaging the ground or floor, the folded scaffold may be readily wheeled, similar to the manner in which a wheel barrow is maneuvered, to a convenient storage or other location. The two forward wheels, being situated above the ground do not obstruct the wheeling movement of the folded scaffold.

The scaffold 10 may be restrained in the folded position against inadvertent unfolding by exerting a force, preferably upon the arcuate member 16 in the direction of the arrow 240 (FIGURE 9). This force relatively arcuately displaces theparallel, spaced guard rail sec tions 73 and the front support members 14 about the pin connection 72. Thus, the section 73 and the front upright support member 14 are displaced from the position shown in dotted lines in FIGURE 9 to the position shown in solid lines. Hence, the guard rail sections '73 are snapped over the forward members 14 and become disposed at a slight acute angle to the left with respect to a plane containing the centerline of each member 14.

A considerable force must be exerted, preferably at the arcuate member 16 in the general direction of the arrow 242 in order to displace the guard rail sections 73 from their position shown in solid lines in FIGURE 9 into the position shown in dotted lines to accommodate unfolding of the scaffold.

THE EMBODIMENT OF FIGURES 10 AND 11 If desired, the telescopic legs, generally designated 25!) in FIGURES 10 and 11, may be provided with a manual rack and gear mechanism, generally designated 252 for 8 incrementally varying the effective length-of the legs, i.e. the height of the platform 42 above the floor.

In the schematic representations of FIGURES 10 and 11, a vertical member 254 telescopically extends within each upright support member 14 being retained therein by the meshing of the teeth of a pinion gear 256 with the rack teeth 258 disposed along one edge of the vertical member 2 54.

The two pinion gears 256 are non-rotatably secured by suitable means to a cross shaft 260, the cross shaft being suitably mounted to the transverse channel member 30 by anti-friction bearings 262 of suitable type. A crank han-. dle 264 is pivotally connected to one end of the cross shaft 260 by a pin.

Thus, appropriate rotation of the crank handle 264 jointly rotates the shaft 260 and the pinion gears 256 correspondingly lowering or elevating the associated castors 174 to the desired height above the floor. Once the desired height has been established, the crank handle 264 may be pivoted about its pin connection to the shaft 260 into a position immediately adjacent the scaffold frame. Suitable means (not shown) should be provided to retain the handle 264 and the shaft 261) against inadvertent rotation during use of the scaffold. As a safety feature, a suitably configurated shield 270 may be secured to the channel 31 to shield the pinion gears 256 and the cross shaft 260.

The invention may be embodied in other specific forms Without departing from thespirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a folding scafiold of the household type, a frame comprising vertically-extending supports at each end of the scaffold, a centrally hinged standing platform carried by the frame means, said frame means enclosing one end and both sides of the scaffold, thereby retaining an access at the open end, and said frame means including collapsible side guard rails each comprising hinged rail sections, at least a pair of essentially parallel diagonal struts each having variable effective length and being pivotally joined between one vertically-extending support at one end of the scaffold and a rail section adjacent the opposite end of the scaffold such that progressive folding of the scaffold continuously extends the effective length of each said diagonal strut and progressive unfolding continuously reduces the effective length.

2. A scaffold as defined in claim 1 further including a material-holding platform disposed at the end of the scaffold opposite the access opening and optionally positionable in a vertical or a horizontal orientation.

3. A scaffold as defined in claim 1 wherein the access opening is provided with a safety belt selectively fastenable between spaced vertically-extending supports.

4. A scaffold as defined in claim 1 wherein said extensible-retractable diagonal struts each comprise telescopic composite rod means comprising a central tubular member into which upper and lower tubular members of reduced diameter respectively extend, said upper and central tubular members being united by means for accommodating relative radial rotation therebetween and said lower and central tubular members being united by means which selectively restrain the tubular members in fixed relation one to another when the scaffold is in the fully extended position and accommodates said relative radial rotation and relative axial displacement between the lower and the central tubular members when the scaffold is being folded and unfolded.

5. In a selectively collapsible mobile scaifold, a frame, a work platform carried by the frame and comprising adjacent platform sections each hinged one to another, a pair of elevated guard rails each comprising elevated rail sections hinged one to another, a set of floor-engaging wheels carried by the frame at the ends thereof upon extensible legs to accommodate (1) adjustment of the height of the platform with respect to the floor and (2) leveling of the platform when different floor elevations are encountered.

6. A scaffold as defined in claim 5 wherein each said extensible leg comprises slideably joined telescopic members each member being provided with spaced detent apertures and each leg further comprising a spring-loaded detent pin selectively insertable into aligned apertures in said telescopic members to individually establish the desired effective length of each leg.

7. A scaffold as defined in claim 5 wherein the extensible legs at least one end of the scafiold each comprise relatively displaceable telescopic members, one of said telescopic members being provided with a rack of teeth which meshes with a toothed gear and means for selectively rotating the gear to incrementally select the desired effective length of the leg.

8. A scaffold as defined in claim 5 wherein at least one said leg carries a weight-actuated brake which engages the adjacent wheel to prevent rotation thereof once the user occupies the work platform.

9. In a method of collapsing a folding scaffold between extreme essentially self-restrained position, the scaffold having a frame, upright supports at each end of the frame, a hinged platform and hinged sectional guard rails each pivotally carried by the frame, and diagonal struts each respectively disposed between a section of the guard rail and an upright support, the steps of: releasing at least selected ones of the diagonal struts from a restrained position, relatively axially displacing the ends of the scaffold toward each other by pivotally elevating the hinged portions of the guard rails and the platform as said selected ones of the diagonal struts are lengthened, bringing the ends of the scaffold into side-by-side collapsed relation so that spaced essentially parallel guard rail sections are disposed at a slight acute angle at one side of the longitudinal axis of the adjoining upright supports, and restraining the scaffold in the fully collapsed position by displacing said guard rail sections across the longitudinal axis of the adjoining upright supports so that said guard railsections are disposed at a slight acute angle at the other side of the longitudinal axis.

10. In a folding scaffold, a frame including support members at each end of the frame, a centrally-hinged work platform pivotally connected to the support members, a pair of centrally-hinged guard rails also pivotally connected to the support members and a vertical strut pivotally attached to the central hinge of each guard rail and to the central hinge of the platform to accommodate joint folding and unfolding action of the guard rails and the platform between extended and collapsed scaffold positions.

11. In a folding scaffold, a frame including support members at each end of the frame, a centrally hinged Working platform pivotally connected to said support members, a pair of centrally hinged guard rails also pivotally connected to the support members at an elevation above said platform, and a pair of diagonal struts each having variable effective length and each being pivotally joined between one of said supports at one end of the scaffold and a guard rail section at the opposite end of the scaffold, said platform and said guard rails being foldable at said hinged portions and said struts varyingin length upon such folding to accommodate collapsing of said scaffold for convenient storage thereof.

References Cited by the Examiner UNITED STATES PATENTS 2,285,901 6/1942 Chenoweth 182152 3,190,406 6/1965 Usher 182-152 3,212,605 10/1965 Dickerson 182152 3,235,038 2/1966 Nesslinger 182-152 REINALDO P. MACHADO, Primary Examiner. 

11. IN A FOLDING SCAFFOLD, A FRAME INCLUDING SUPPORT MEMBERS AT EACH END OF THE FRAME, A CENTRALLY HINGED WORKING PLATFORM PIVOTALLY CONNECTED TO SAID SUPPORT MEMBERS, A PAIR OF CENTRALLY HINGED GUARD RAILS ALSO PIVOTALLY CONNECTED TO THE SUPPORT MEMBERS AT AN ELEVATION ABOVE SAID PLATFORM, AND A PAIR OF DIAGONAL STRUTS EACH HAVING VARIABLE EFFECTIVE LENGTH AND EACH BEING PIVOTALLY JOINED BETWEEN ONE OF SAID SUPPORTS AT ONE END OF THE SCAFFOLD AND A GUARD RAIL SECTION AT THE OPPOSITE END OF THE SCAFFOLD, SAID PLATFORM AND SAID GUARD RAILS BEING FOLDABLE AT SAID HINGED PORTIONS AND SAID STRUTS VARYING IN LENGTH UPON SUCH FOLDING TO ACCOMMODATE COLLAPSING OF SAID SCAFFOLD FOR CONVENIENT STORAGE THEREOF. 